Nowadays, there are numerous types of massage pools, also known as whirlpools or spas, and swimming massage pools or swim spas, which are massage pools of larger dimensions suitable especially for active swimming. Spas or swim spas are used for relaxation and rehabilitation and they are also designed to complement houses and villas, both in the interior and the exterior. Spas and swim spas range in ground plan size from approximately 1×2 m for a spa up to 3×6 m for a swim spa. The structure of spas and swim spas is designed to keep the water clean and warm for a long time. This is achieved by an insulated structure of a shell and a thermo-insulating cover, which prevents leakage of moisture and heat from the spa or swim spa, thus reducing the operation costs. Moreover, the cover prevents injuries of young children and pets, protects the massage pool from contamination with impurities and dust, and prevents penetration of solar radiation that causes microorganisms to multiply in the water. Even though thermo-insulating covers are made from a lightweight material, their weight is still relatively great with respect to their dimensions, which makes these covers difficult to handle. The most commonly used thermo-insulating covers consist of two thermo-insulating segments, which are rotatably connected to each other and are manually moved from a closed position to an open position and vice versa. In the closed position, at the beginning of the handling operation, one thermo-insulating segment is folded over the other so they touch each other with their originally upper sides, and subsequently they are removed, whereby two persons are usually necessary for the removal. Another disadvantage of manual removal of the thermo-insulating cover is a problem of storing the thermo-insulating cover while the spa or swim spa is used.
Therefore, devices for manipulation of the segments of thermo-insulating covers between theft closed position and open position have been developed, including both manually controlled mechanical devices and semi-automatic devices, as well as automatic devices reacting only to commands from an operator.
U.S. Pat. No. 5,689,841, for example, discloses a mechanism for lifting a two-segment thermo-insulating cover from a spa or swim spa by means of a device by which the first thermo-insulating segment is rotatably connected to the spa. When moving the thermo-insulating cover to a storage position, at first the second thermo-insulating segment is raised and folded back over the first thermo-insulating segment, and so both segments touch each other with their originally upper sides. After that the first thermo-insulating segment is raised to a vertical position along with the second thermo-insulating segment by means of a lifting device and, as a result, the spa is uncovered.
Similar mechanisms have been described, for example, in documents U.S. Pat. No. 6,795,984, US2007/0209104 and U.S. Pat. No. 6,000,071. Nevertheless, in all these solutions, during the time when the spa is used, the thermo-insulating cover remains on the edge of the spa in a vertical, i.e. storage position, in which it impedes access to the massage spa from one of its sides and restricts the view. Storing the thermo-insulating cover in another position while the spa is used is partially solved, for example, by solutions disclosed in U.S. Pat. Nos. 7,155,756, 5,048,153, 5,974,600 or WO2007/058953, in which the thermo-insulating cover, after being raised from the upper circumference of the spa, is lowered or dropped to a space outside the ground plan of the massage pool, for example, beside the back wall of the spa. However, similarly as in the case of the above-mentioned solutions, it is first necessary to fold the second thermo-insulating segment over the first thermo-insulating segment so that they touch each other with their originally upper sides, which is in most cases performed manually. Still, there is a problem with the difficult manipulation of the thermo-insulating cover, the weight of which is considerably high.
U.S. Pat. No. 7,155,756 discloses a mechanism for automatic folding of a second thermo-insulating segment over a first thermo-insulating segment to a position described in the above-mentioned solutions. This mechanism is rather complicated and puts great demands on the construction of the entire lifting device, which also increases its acquisition and operating costs. Moreover, the aesthetic impression is significantly worsened. All the devices for manipulation of thermo-insulating covers according to the background art must be dimensioned for lifting the entire weight of both thermo-insulating segments or for rotating the entire weight of both thermo-insulating segments, which means that these devices are bulky and their cost increases.
In all these cases of manipulation, it is always the bottom side of the cover that remains visible after the cover is lifted and folded. The bottom side is always degraded in terms of appearance and surface, since it is exposed to the aggressive wet environment and chemical substances in the water and vapors under the cover when closed. The bottom side of these covers may be non-hygienic for touch, as well as for breathing.
CZ PV 2008-243 (WO 2009/129756) discloses a method of manipulation of a thermo-insulating cover of a spa or a swim spa between its covering position and opened position. The cover comprises a pair of thermo-insulating segments consisting of a carrier thermo-insulating segment and a carried thermo-insulating segment, which are rotatably connected to each other and in the covering position are lying with their bottom surfaces on the circumference of the spa or swim spa. The carrier thermo-insulating segment is rotatably mounted on the spa or swim spa. During the phase of opening, the carrier thermo-insulating segment is rotated and its front end is raised, carrying the carried segment. After the carrier segment reaches a vertical position, the carried segment is drawn by force to the carrier segment, until both segments touch each other with their bottom surfaces. In the opened position, therefore, the original upper sides of the segments are on the outside side of the raised pair of segments, which is advantageous compared to the previous solutions. Although the method allows the thermo-insulating spa or swim spa cover to be opened and closed reliably, the operation of opening as well as closing is performed in two steps, each step requiring a separate device arranged on each side of the cover—two devices for the rotation of the carrier segment and two devices for bringing the carried segment closer and removing it, which increases costs and reduces reliability. Both segments can be lowered together to a storage position in a storage space, but two additional means for lowering and extending the thermo-insulating segments are needed.